The invention is generally directed to a handle for a package. More particularly, the invention involves a unique pivoting handle attachable at the upper closure strip of a multiple ply bag of the type used for packaging bulk comodities, such as powdered milk, granular compounds, fertilizer, seed and the like.
It has been a desire in the packaging industry to construct a thin flexible handle for multiple ply bags. Prior art handles, usually made of paper or molded plastic, have inherent deficiencies in that either they cannot be substantially flattened against the bag for wrinkle-free storage and subsequent filling procedures, or do not provide a comfortable carrying grip for the purchaser of the packaged goods.
Some previous attempts at providing a foldable bag handle have involved the use of a folded tape or strapping, as exemplified by U.S. Pat. No. 2,625,318 to Ross. This patent shows the use a strip of relatively strong flexible paper in order that a 90.degree. fold may be obtained. However, a flexible strip or handle for a multiple ply bag, such as well known side-gusseted multiple ply bags with pinched end closures, would cause serious difficulties in the bag handling process. Many automated bag handling machines require that, if a handle is provided, it remain in close proximity to the package exterior. If the handles flex to bend away from the package exterior jamming of the filling and handling equipment occurs.
Prior art handle designs have often required a folded tape or flexible paper handle to be glued and/or sewn to a paper bag. This type of affixing provides an inadequate jointed connection for most multi-wall paper bags. The inadequacy stems from the weak connection, since only the outer wall of the paper bag is glued-bonded to the handle. Because three or more plies of paper are often employed in modern day multi-wall bags, there would be no anchoring possible to the other inward plies. This is further compounded in that typically the outer bag, to which such a handle might be glued, is relatively weak and is designed for the application of appealing graphics for point-of-sale attraction of consumers.
Previous attempts at sewing flexible handles to multi-ply bags have resulted in weakened attachments. Conventionally multi-walled bag closures and strips are sewn with three to four stiches per linear inch. This known pattern density has developed through years of practice in the industry. More dense patterns, greater than four, tend to perforate the paper to the degree that it causes closure end weakness. As a result, the bag tends to "zipper" open, similar to the perforate lines of separation between paper towel segments on a roll. On the other hand, less dense patterns, less than three, tend to create leakage of the package commodity, which is often a powdered material, such as dry milk, because wide gaps are left between stiches. As a result, the type of flexible handles as typified in the U.S. Pat. No. 2,625,318 would provide a handle that, although narrow enough to fit a normal person's hand, would not provide sufficient width at the sewn connection to be held by an adequate number of stitches.
Through experimentation, the inventors have found that the width of the material used in the handle base for attachment to the closure strips of a multi-wall bag, particularly of the type for commodities weighing from about twenty to thirty pounds, needs to be about 11/2 inches in width to be anchored properly to the bag. If narrower handles bases are used, there is not sufficient distribution of the load over wide enough area of the package. Narrower bases lead to a damaging condition in that the handle will loosen the threaded closure. As a result, the package is susceptible of tearing away from the handle bond areas. Accordingly, a major object of the present invention is to provide a handle that distributes the loading force over a sufficiently wide area so that damage to the bag closure and handle attachment do not occur.
The inherent difficulties in using folded, or thick single ply paper strips, as handles is the extreme difficulty in the handling techniques for known bag making machinery. Therefore, the industry has moved toward the use of plastic handles, which allow for greater strength. Heretofore, the use of plastic handles created other problems by not providing sufficiently thin contours that allow multi-walled bags to be fed through bag handling and filling machinery.
The thickness of plastic handles is usually directly proportional to the weight to be carried. For example, in a standard bag of about twenty to twenty-five pounds content, even a dense paper handle would require a material thickness of greater than 0.040 inches in order to be adequate to hold the bag weight without tearing. Of course, the thickness of a paper handle doubles when folded over, as has been typical in prior art paper handle constructions. When a folded paper handle has been required to lie flat against a bag surface, it accentuates the thickness of the handle above the exterior bag surface. Folding can cause a 0.040 inch paper stock to become 0.100 inches or more when folded into the shape of a handle grip. In fact, the resultant handle creates a thickness greater than the dimensional thickness of the bag taken through standard side gussetted areas. Also of great importance in the industry is that when multi-walled bags are stacked, the handle areas can cause "pillars" to build vertically within stacked bundles. These "pillars" cause bag wrinkling to occur. Bag wrinkling is the nemesis of multi-wall bag handling. The wrinkles can cause bag failure when using standard automated bag filling machines. The elimination of bag wrinkling is a primary goal of the present invention.
Equal to the need to eliminate bag wrinkling, is the desire to provide a thin flexible handle that is comfortable to grasp. While the construction of polyethylene handles in various configurations is known, none has provided a sufficiently hingeable handle that allows for a comfortable grip area to be offered to the consumer for lifting and carrying a heavy bag. When present day plastic handles are molded to have a very thin profile in order to lie flat against the exterior of the flattened bag prior to filling, they create a sharp gripping edge, which can cut into the purchaser's hand. As a result the invention is directed toward providing a flat contour for bag handling and elimination of wrinkling, a sufficiently strong handle to carry the load, an attachment provision that does not tear out normal stiched closure strips, and lastly, a comfortable grip for the purchaser.